This is a Phase 2 exploratory study being conducted to evaluate the efficacy and safety of EB-1020 SR in treating adult male patients who meet DSM-IV-TR diagnostic criteria for ADHD on the M.I.N.I.-Plus. Evaluations include determining an effectiveness signal for ADHD and related symptoms and exploring dosing, tolerability, onset of action, and duration of effect. Dose-response/tolerability relationships with EB-1020 SR will also be explored. The 1-week placebo lead-in also will be used for informal safety comparison purposes.